It has nothing to do with gravity, that is a constant. We are dealing with distance the bullet travels. A straight line is the shortest distance between two places. When correcting for wind, your bullet is no longer traveling in a straight line (left to right wise) since you have to aim into the wind since it it going to blow it over. Thus your bullet trajectory (again, left to right) is not straight, it is curved. A curved line is longer than a straight one, thus the bullet had to travel a longer distance, thus its flight time was longer. This results in a lower impact, by a tiny amount. But again, its splitting hairs, the flight time is milisconds different, generally small enough to ignore.
Originally Posted by buggsb
First, the effect of gravity on bullet drop is completely unrelated to the distance traveled.